Most digital cameras today can enable video capture. Examples of consumer products include regular cameras, portable hand-held electronic devices, and other movable devices. Some of these consumer devices may use complementary metal oxide semi-conductor (CMOS)-based camera sensors. Most CMOS sensors use rolling shutter (RS) mechanism, as opposed to using a global shutter (GS), e.g., charge-coupled device (CCD)-based camera sensors. In a RS camera, detector rows are read and reset sequentially. Each row of the CMOS sensor is exposed during a slightly different time window. Since pixels are acquired at different points in time, motion of either the camera or the imaged object may cause geometrical distortion in the captured images. The geometric distortion may be exaggerated when the RS camera is coupled to a movable object, such as an unmanned aerial vehicle (UAV). In some instances, motion of the movable object may cause the resulting image to be tilted or skewed at an angle.
In some cases, video quality can be improved using mechanical systems. For example, mechanical image stabilization (MIS) systems can be used to actuate the camera lenses or CMOS image sensor, to compensate for small pan and tilt rotational motions. MIS systems can stabilize images substantially in real-time, and do not require significant computation (e.g., image processing) by the camera. However, MIS systems may be unable to compensate for rapid high frequency motions, such as those caused by vibrations from a vehicle engine. Moreover, MIS systems are generally not suitable for most consumer-based digital cameras due to their costs and form factor.